A Possible 1.8 K Refrigeration Cycle for the Large Hadron Collider
The Large Hadron Collider (LHC) under construction at the European Laboratory for Particle Physics, CERN, will make use of superconducting magnets operating below 2.0 K. This requires, for each of the eight future cryogenic installations, an isothermal cooling capacity of up to 2.4 kW obtained by vaporisation of helium II at 1.6 kPa and 1.8 K. The process design for this cooling duty has to satisfy several demands. It has to be adapted to four already existing as well as to four new refrigerators. It must cover a dynamic range of one to three, and it must allow continuous pump-down from 4.5 K to 1.8 K. A possible solution, as presented in this paper, includes a combination of cold centrifugal and warm volumetric compressors. It is characterised by a low thermal load on the refrigerator, and a large range of adaptability to different operation modes. The expected power factor for 1.8 K cooling is given, and the proposed control strategy is explained.
KeywordsLarge Hadron Collider Centrifugal Compressor Suction Pressure Cooling Capacity Screw Compressor
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- 1.The LHC study group, “The Large Hadron Collider, Conceptual Design,” CERN Report/AC/95–05(LHC)Google Scholar
- 2.U. Wagner, “The LHC refrigerators with surface-located cold boxes for the temperature range 300–4.5 K,” LHC Project Note 70 (1996)Google Scholar
- 4.Ph. Lebrun, G. Riddone, L. Tavian and U. Wagner, Demands in refrigeration capacity for the Large Hadron Collider, in: “Proceedings of ICEC 16,” T. Haruyama, T. Mitsui, K. Yamafuji, ed., Elsevier Science (1997), p. 95–98Google Scholar